412 R. BuUen Newton — Fossils from Sarawak, Borneo. 



sandy material, and stands out in relief on a greyish blue-black 

 compact limestone intersected with, veins of calcite, and bearing 

 a water-worn surface. An accompanying manuscript label gives 

 the following information : — " Borneo. Ostrea coliibrina ? Goldf., 

 pi. Ixxiv, fig. 5. M.P.G. " ; the latter letters pencilled on the corner 

 implying that the specimens were transferred from the Museum 

 of Practical Geology to the British Museum during the year 1880. 



Considering the extent of Borneo, said to thrice exceed the 

 superficial area of Great Britain, it is to be regretted that no more 

 j^recise locality has been preserved with the specimens, although 

 a comparison with some further limestones from the same island 

 has enabled me to partially supply this information. I refer to 

 material in the Geological Society's Museum (presented by 

 Mr. Jas. Eussell in 1861) localized as from " Bousoe " (probably 

 Busau), and to other specimens in the British Museum, presented 

 by Mr. A. H. Everett a few years since, from Bidi, Busau, 

 Jambusau, Sadong, etc., all of which localities are situated in the 

 north-western part known as the Residency of Sarawak,^ on or near 

 the river of the same name. These limestones possess similar 

 petrographical characters and the same water-worn appearance, 

 though several of them present whitish, decomposed, weathered 

 surfaces, besides having their fossiliferous structures (corals, etc.) 

 more or less elevated above the general level of the matrix ; 

 so marked is this resemblance that I have no doubt the molluscan 

 remains were obtained from the Sarawak River District, and most 

 probably from either Bidi or Busau. 



I may here insert the following observations on the geology of 

 this part of Borneo, published by Mr. A. H. Everett- in 1878 : — 

 "This district consists of an ancient blue limestone (Palaeozoic?), 

 on which is superimposed unconformably "a thick series of sand- 

 stones, conglomerates, and clay-shales, constituting the most ex- 

 tensive series of beds in this part of Borneo ; and on these last 

 lie strata of clay-shales, alluvial clay, river gravels, etc., of very 

 recent origin. Piercing the limestone and sandstone we find granite 

 and a variety of igneous and trappean rocks — basalt, porphyrite, 

 greenstones, etc., these latter being developed in great abundance in 

 the antimony districts where they are in immediate contact with 

 the limestone. The latter formation, in which the lodes of antimony 

 are seen in situ, is locally rich in fossil organic remains, but I am 

 unable to say whether they have been examined by a competent 

 geologist with a view to approximate the age of the rock ; the 

 planes of stratification can seldom be made out with any approach 

 to certainty, but where they are evident they show that the 

 originally horizontal beds have been uptilted almost on end and 

 much denuded ; and there is abundant proof that a very considerable 

 interval in time elapsed between the close of the limestone 

 formation and the commencement of the succeeding sandstone series." 



^ See map of this region by W. M. Crocker ia the Proc. Eoy. Geogr. Soc. 1881, 

 N.S., vol. iii, p. 256. 



'^ "Notes on the Distribution of the Useful Minerals in Sarawak" : Journal 

 Straits Branch Eoyal Asiatic Society, 1878, p. 14. 



